JP2002181550A - Angular-velocity measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a package without having a bad influence on the function of a vibration-type gyroscope in an angular-velocity measuring apparatus in which a vibrator and a support substrate are housed inside the package. SOLUTION: The angular-velocity measuring apparatus 1A detects a rotation angular velocity around a prescribed rotation axis Z. The apparatus is provided with the vibrator 12, a vibrator support member 9 supporting the vibrator 12, a circuit board 6 supporting the support member 9 and a semiconductor integrated-circuit chip 8 used to control the signal of the vibrator. The chip 8 is flip-chip-mounted on the circuit board 6, and the support member 9 is installed on the chip 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity measuring device using a vibratory gyroscope.

[0002]

2. Description of the Related Art Recently, the use of a vibratory gyroscope as a rotation speed sensor used in a vehicle rotation speed feedback type vehicle control method of an automobile has been studied. A vibratory gyroscope is an angular velocity sensor that uses a Coriolis force caused by rotation of a vibrator, and measures an angular velocity by electrically oscillating the vibrator and simultaneously detecting vibration induced by the Coriolis force. In such a system, the direction of the steered wheels is detected by the rotation angle of the steering wheel. At the same time, the rotational speed at which the vehicle body is actually rotating is detected by a vibratory gyroscope. Then, the direction of the steered wheels is compared with the actual rotational speed of the vehicle body to obtain a difference, and the wheel torque and the steering angle are corrected based on the difference, thereby realizing stable vehicle body control.

In such a vibratory gyroscope, it is necessary to fix the vibrator to a container such as a can package, house the vibrator together with a circuit in a predetermined housing, and attach the housing to a vehicle body. In this case, the vibrator is attached to the support substrate, and after attaching the semiconductor integrated circuit chip to the support substrate, the support substrate is attached to the base of the can package by pins.

For example, in Japanese Patent Application Laid-Open No. 2000-9476, when a tuning-fork type vibrator is fixed on a supporting substrate and the vibrator and the supporting substrate are accommodated in a package, vibration applied to the package from the outside may be reduced. In order to prevent the vibrator from swinging and being damaged by the impact, a swing preventing member is provided.

[0005]

In such a vibratory gyroscope, it is required to reduce the planar dimension of the package and the height of the package. However, a technique for reducing the size of the package without adversely affecting the function of the vibratory gyroscope has not been sufficiently studied.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the size of an angular velocity measuring device which accommodates a vibrator and a supporting substrate in a package without adversely affecting the function of the vibrating gyroscope.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an angular velocity measuring device for detecting a rotational angular velocity about a predetermined rotation axis, comprising: a vibrator; a vibrator supporting member for supporting the vibrator; A semiconductor integrated circuit chip for controlling a signal of the vibrator, wherein the semiconductor integrated circuit chip is flip-chip mounted on the circuit board. The vibrator support member is provided on a circuit chip.

The inventor has devised a structure in which a semiconductor integrated circuit chip is flip-chip mounted on a circuit board, and a vibrator is supported on the chip via a vibrator supporting member. Thereby, the vibrator, the driving system of the vibrator, and the processing system of the detection signal from the vibrator are not adversely affected.
The angular velocity measuring device was significantly reduced in size.

Preferably, the vibrator is formed along a predetermined plane, and the predetermined plane is substantially perpendicular to a rotation axis of the vibrator.

[0010] Here, that the vibrator is formed along the predetermined surface means that the vibrator is formed on the predetermined surface in a strictly geometrical sense because the vibrator has a thickness. It doesn't make sense. If the vibrator is formed within a thickness of about 1 mm when viewed from a predetermined surface, the present invention is included in the present invention.

The predetermined plane substantially perpendicular to the rotation axis does not mean that the plane is strictly perpendicular to the geometrical shape, but naturally includes a manufacturing error and the like. The angle may be within 5 ° from a direction strictly perpendicular to the direction. Such a vibrator is called a so-called "transversely placed" vibrator. In the case of a vibrator that adopts such an installation method, the present invention is particularly excellent in terms of reduction in package height and reduction in lateral dimension.

Preferably, the semiconductor integrated circuit chip extends substantially parallel to the vibrator. In this case, the invention is particularly advantageous in terms of reducing the height of the package and reducing the lateral dimensions.

The type of the semiconductor integrated circuit chip is not particularly limited, but is preferably a semiconductor integrated circuit chip for controlling the driving signal and the detection signal of the vibrator.
SIC (Application Specified Integrated Circuit:
Application specific integrated circuits) are preferred.

When a semiconductor integrated circuit chip is flip-chip mounted and a vibrator is supported on the chip via a vibrator support member, the vibrator, the vibrator support member, the circuit board and the semiconductor integrated circuit chip are packaged. Can be accommodated inside. FIG. 1 is a sectional view schematically showing an angular velocity measuring device 1A according to this embodiment.

In manufacturing the device shown in FIG. 1, first, a chip component 7B is set on the front surface 6b of the circuit board 6, and a chip component 7A is set on the back surface 6c. Also, the surface 6 of the circuit board 6
The semiconductor integrated circuit chip 8 is flip-chip mounted near the center of b. The flip chip mounting itself is a known mounting method. First, the chip 8 is placed in a state where the surface of the chip 8 is in contact with the surface of the circuit board 6.
Is filled with plastic.

Next, the circuit board 6 is connected to the can package base 3. In this example, a through hole 3b is provided in the can package base 3, and the pin 5 is passed through the through hole 3b. Further, the through hole 6a is passed through the circuit board 6 and the through hole 6a is formed.
Pass the pin 5 through a. Then, the circuit board 6 and the pins 5 are soldered.

Next, the vibrator 12 is supported on the semiconductor integrated circuit chip 8 via the support member 9. The support member 9 includes, for example, a metal pin 10, and an adhesive layer 11 that connects the pin 10 to the back surface 12 b of the vibrator 12. One end of a wire 13 is connected to the surface 12 a of the vibrator, and the other end of the wire 13 is connected to a surface 6 b of the circuit board 6. Then, the end of the can package lid 2 is resistance-welded to the end flange 3 a of the base 3 via the welding portion 4.

The vibrator 12 extends substantially along the XY plane. The rotation axis of the vibrator 12 is the Z axis, and the vibrator 1
2, the angular velocity of the rotation ω about the rotation axis Z is measured.

The present invention also relates to an angular velocity measuring device for detecting a rotational angular velocity around a predetermined rotation axis, comprising: a vibrator, a vibrator supporting member for supporting the vibrator, and a signal for the vibrator. A semiconductor integrated circuit chip for performing, a ceramic circuit board supporting the vibrator support member, and a lid to be combined with the ceramic circuit board, a container is constituted by the ceramic circuit board and the lid,
A vibrator and a vibrator support member are housed in a container.

As described above, by installing the vibrator on the ceramic circuit board via the vibrator support member, the stand-off from the motherboard, which is required in the can package, becomes unnecessary, and after mounting the vibrator, The height of the package can be reduced. In addition, in the case of a can package, it is necessary to insert the pins 5 into the through holes and solder them. However, when a ceramic circuit board is used, the pins are not used and the surface of the ceramic circuit board is not used. Can be connected by soldering to the connection terminal (land).
Therefore, there is no possibility that the pin is broken or damaged. Also, when an external impact is applied to the package,
For example, if the sensor is directly hit, the pin may be twisted and an erroneous signal may be generated. However, such an erroneous signal can be prevented.

FIG. 2A shows a ceramic circuit board 18A.
FIG. 2 is a cross-sectional view schematically showing a package 15 using the same.

The flat plate portion 18c of the ceramic circuit board 18A
The support member 9 is installed on the inner wall surface 18e of the, and the vibrator 12 is bonded to the support member 9. 18d is an outer surface of the flat plate portion 18c. The side wall portion 18b rises along the outer periphery of the flat plate portion 18c, and the lid 1 is attached to the side wall portion 18b.
6 is covered, and constitutes the container 15. Container 1
The vibrator 12 and the support member 9 are accommodated in an inner space 17 of the fifth element 5. The step portion 18a further projects from the flat plate portion 18c. A wire 13 is provided on the surface 12a of the vibrator 12
Is connected, and the other end of the wire 13 is connected to the step 18a.

As described above, by providing the wire bonding from the vibrator to the stepped portion, the height difference of the wire 13 can be reduced as compared with the case where the stepped portion does not exist. Height can be reduced. At the same time, the width of the wire is reduced by reducing the height difference of the wire.

As described above, in a case where the vibrator and the supporting member are accommodated in the package of the ceramic circuit board, in a preferred embodiment, a mounting member for mounting the semiconductor integrated circuit chip is provided, and the mounting member and the ceramic circuit are mounted. A closed space is formed by the substrate and the semiconductor integrated circuit chip is accommodated in the closed space. FIG. 2B relates to this embodiment.

The angular velocity measuring device 1B shown in FIG.
An installation member 19 is provided in addition to the container 15 of FIG. This installation member 19 is a ceramic circuit board. The chip 7 is provided on the outer surface 19e of the circuit portion 19c of the installation member 19.
A is installed, and the chip 7B is also installed on the inner side surface 19d. A semiconductor integrated circuit chip 28 is provided on the inner surface 19d, and the chip 28 and an electronic circuit (not shown) are connected by wire bonding 13. The installation member 19 further includes peripheral wall portions 19b and 19
a. The peripheral wall 19a is joined to the container 15 to form a closed space 20.

In the present embodiment, the portion of the ceramic circuit board 19 on which the semiconductor integrated circuit chip is mounted is separated from the portion of the ceramic circuit board on which the vibrator is accommodated, so that there are few restrictions on the design of the electronic circuit.

Preferably, the semiconductor integrated circuit chips 8, 2
The vibrator 8 and the vibrator 12 exist at overlapping positions when viewed in the Z-axis direction. In other words, when the chip 28 and the vibrator 12 are both projected on the XY plane and viewed, they overlap. Thereby, the overall width of the package can be further reduced.

Although the semiconductor integrated circuit chip 28 may be mounted by flip chip mounting, a normal mounting method may be used.

The back surface 18d of the ceramic circuit board 18 opposite to the facing surface (inner wall surface) 18e facing the lid 16 is provided.
A semiconductor integrated circuit chip can be placed thereon. This embodiment is particularly excellent in that the height of the entire package can be reduced.

FIG. 3 is a sectional view schematically showing an apparatus 1C according to this embodiment. This ceramic circuit board 18
A further includes a peripheral wall portion 18f. The semiconductor integrated circuit chip 28 is attached to the outer wall 18d of the flat plate 18c in addition to the chip 7A. This chip 28
May be flip-chip mounted or a normal mounting method.

In the angular velocity measuring device 1D shown in FIG. 4, the semiconductor integrated circuit chip 8 is flip-chip mounted on the inner wall surface 18e of the flat plate portion 18c of the ceramic circuit board 18B. A vibrator 12 is provided on the chip 8 via a support member 9. Reference numeral 17 denotes an inner space of the package.

According to this embodiment, similarly to the apparatus of FIG. 3, the height of the package can be minimized and the flat plate portion 18c
The area of the surface (bottom surface) 18d can be minimized.

FIGS. 5 to 10 are perspective views of ceramic circuit boards for mounting and housing the vibrator, respectively. However, the lids are omitted.

In the ceramic circuit board 18A of FIG. 5, for example, four step portions 18a are provided.

The circuit board 18B shown in FIG. 6 has no steps. Particularly preferably, for example, as shown in FIG. 6, the driving vibration mode Vd and the detection vibration mode vt of the vibrator are substantially in a predetermined plane.

In the circuit board 18C shown in FIG. 7, for example, step portions 18f are provided at eight places. That is, the step portion 18a shown in FIG. 5 is divided into two to obtain a step portion 18f having a smaller width.

The ceramic circuit board 18D shown in FIG. 8 is provided with an arc-shaped step 18g.

The ceramic circuit board 18E shown in FIG. 9 is provided with a quadrangular step 18h, and the tip of the step 18h is thickened.

In the ceramic circuit board 18j of FIG. 10, a quadrangular step 18g is provided, and the tip of the step 18j is made thin.

In the present invention, a combination of a glass epoxy substrate and a metal shield plate can be used instead of the can package.

Further, the present invention relates to an angular velocity measuring device for detecting a rotational angular velocity around a predetermined rotation axis,
A vibrator, a vibrator support member supporting the vibrator, a circuit board supporting the vibrator support member, and a semiconductor integrated circuit chip for controlling a signal of the vibrator. The vibrator is mounted on the front surface via the vibrator support member, and the semiconductor integrated circuit chip is mounted on the back surface of the circuit board by bare die bonding and wire bonding. The pin fixed to the can package is connected by a silver paste, and a can package lid is hermetically welded to the can package base.

As described above, the semiconductor integrated circuit chip is mounted on the circuit board by bare-die bonding and wire bonding. However, since the semiconductor integrated circuit chip is mounted on the back surface of the circuit board, the semiconductor integrated circuit chip and the wire bond are mounted. Potting for protection is not required, and the semiconductor integrated circuit chip is sandwiched between the circuit board and the can package base. There is an advantage that the possibility of touching the semiconductor integrated circuit chip and the bonding wire is reduced, and the semiconductor integrated circuit chip and the bonding wire are effectively protected from damage. Further, since the circuit board and the pins fixed to the can package base are connected by the silver paste, cleaning is not required.

FIG. 11 shows such an angular velocity measuring apparatus 1E.
FIG. 2 is a cross-sectional view showing the configuration of FIG. 1, and the same parts as those shown in FIG. When manufacturing the device of FIG. 11, first, the chip component 7
B and the chip component 7A on the back surface 6c. Further, the semiconductor integrated circuit chip 8 is bare-die bonded near the center of the back surface 6c of the circuit board 6, and the wire 13 is wire-bonded. In the embodiment shown in FIG. 1, the surface of the semiconductor integrated circuit chip 8 is placed in contact with the surface of the circuit board 6, and then the exposed rear side of the chip 8 is potted to cover it with plastic. However, in the present embodiment, such potting is unnecessary.

Next, the pins 5 fixed to the can package base 3 are passed through the through holes 6a formed in the circuit board 6, and the circuit board 6 and the pins 5 are connected with silver paste. As described above, since the circuit board 6 and the pins 5 are connected with the silver paste instead of the solder, the cleaning process can be omitted. As described above, since no potting or cleaning is required, the throughput can be improved.

Next, the vibrator 12 is placed on the metal pin 10 and the adhesive layer 1 almost at the center of the surface 6 b of the circuit board 6.
1 is installed via the support member 9 provided with the above. As described above, since the semiconductor integrated circuit chip 8 and the vibrator 12 are mounted substantially at the center of the circuit board 6 so as to overlap each other, the plane size of the angular velocity measuring device 1E can be reduced as in the other embodiments. . In addition, as compared with the embodiment of FIG. 1, the space between the circuit board 6 and the can package base 3 is effectively used, so that the height of the angular velocity measuring device can be further reduced. The vibrator 12 is connected to the circuit board 6 via wires 13 by wire bonding. Next, the end of the lid 2 for the can package is
The end flange 3a of the base 3 is hermetically sealed by resistance welding via a welding portion 4.

As the driving means and the detecting means in the vibrator, any means generally used in the field of the vibrating gyroscope can be employed. When the vibrator is formed of a piezoelectric material, the vibrator is provided with a drive unit and a drive electrode and a detection electrode as a detection unit. Examples of the piezoelectric material include a piezoelectric ceramic such as PZT in addition to a piezoelectric single crystal. Further, when the vibrator is formed of a constant elastic metal, piezoelectric ceramics can be attached on the vibrator as a driving unit and a detecting unit.

The method of supporting the vibrator is not limited, and examples thereof include a bonding method, a method using an adhesive, a method of mechanically fixing with a clamp or the like, a welding method, and a solid phase diffusion method. . However, the bonding method is most preferable from the viewpoint of keeping the detection sensitivity of the vibrator high.

The kind of the adhesive forming the adhesive layer 11 interposed between the vibrator support member main body 10 and the vibrator 12 is not limited, and a synthetic rubber adhesive such as a silicone adhesive or a urethane adhesive may be used. And synthetic resin adhesives such as epoxy adhesives and polyimide adhesives.

It is preferable that the dynamic elastic modulus of the adhesive is 1/100 or less of the dynamic elastic modulus of the vibrator, since the influence on the oscillation state of the vibrator is small. Specifically, when the vibrator material is a piezoelectric single crystal, a piezoelectric ceramic or a constant elastic metal,
It is preferable that the dynamic elastic modulus of the adhesive is 106-108 Pa.

The thickness of the adhesive layer 11 is preferably 1 mm or less, more preferably 0.4 mm or less, from the viewpoint of securely fixing the vibrator. The thickness of the adhesive portion interposed between the support member and the vibrator is such that the change in the Q value of the driving vibration of the vibrator is further reduced over the entire operating temperature range, and the sensitivity of the detected vibration is improved. From, it is preferable to be 0.05 mm or more,
More preferably, the thickness is 0.1 mm or more.

The loss tangent of the adhesive in the adhesive layer 11 is determined in the operating temperature range (normally −30 ° C .− + 85 ° C., particularly preferably −30 ° C.
From the viewpoint that the Q value of the driving vibration of the vibrator can be increased in the entirety of (40 ° C .− + 85 ° C.) and the fluctuation thereof is reduced, it is preferably 0.05 or less. The lower limit of the loss tangent is not particularly limited, and may be 0.00.

The ratio of the maximum value to the minimum value of the loss tangent of the adhesive within the operating temperature range is preferably within three times.

From the viewpoint of making the Q value of the driving vibration of the vibrator more constant, the specific gravity of the adhesive is particularly preferably 1.1 or less. Thus, the specific gravity of the adhesive is set to 1.
In order to approach zero, the filler in the adhesive
Is preferably 7% by weight or less.

In a preferred embodiment, the temperature of the vibrator can be controlled by utilizing the heat generated by the semiconductor integrated circuit chip.
In particular, when the environmental temperature changes in a wide range such as −40 ° C .− + 85 ° C., the ambient temperature of the vibrator is kept within a certain temperature range, for example, 0 ° C .− + 85 ° C. by utilizing heat generated by the semiconductor integrated circuit chip. , Preferably + 25 ° C- +
It can be controlled at 85 ° C. Further, it is possible to maintain a constant temperature by using a cooling effect by using a Peltier element or the like and combining cooling and heating. For example, 0 ° C- + 85
° C, preferably + 25 ° C-+ 85 ° C, and can be controlled to a constant temperature of + 45 ° C or less.

[0055]

As is apparent from the above description, according to the present invention, in an angular velocity measuring apparatus for accommodating a vibrator and a support substrate in a package, the function of the vibratory gyroscope is not adversely affected. Can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an angular velocity measuring device 1A.

2A is a diagram showing a state in which a vibrator 12 is housed in a ceramic package 15, and FIG. 2B is a diagram showing a laminated structure of the ceramic package 15 and an installation member 19 formed of a ceramic circuit board. FIG.

FIG. 3 is a diagram schematically showing an angular velocity measuring device 1C;
A semiconductor integrated circuit chip 28 is mounted on the back surface 18d of the flat plate portion 18c of the ceramic circuit board.

FIG. 4 is a diagram schematically showing an angular velocity measuring device 1D;
Inner surface 18 of flat plate portion 18c of ceramic circuit board 18B
The semiconductor integrated circuit chip 8 is flip-chip mounted on e.

FIG. 5 is a perspective view showing a ceramic circuit board 18A.

FIG. 6 is a perspective view showing a ceramic circuit board 18B.

FIG. 7 is a perspective view showing a ceramic circuit board 18C.

FIG. 8 is a perspective view showing a ceramic circuit board 18D.

FIG. 9 is a perspective view showing a ceramic circuit board 18E.

FIG. 10 is a perspective view showing a ceramic circuit board 18F.

11 is a view schematically showing an angular velocity measuring device 1E, in which a semiconductor integrated circuit chip 8 is mounted on a back surface 6c of a circuit board 6. FIG.

[Explanation of symbols]

1A, 1B, 1C, 1D angular velocity measuring device 2,
16 Lid 3 Can package base 5 pin
8 Flip chip mounted semiconductor integrated circuit chip 9 Support member 10 Support member body 11 Adhesive layer 12 Transducer
13 wire 15 container (ceramic package) 18A,
18B, 18C, 18D, 18E, 18F Ceramic circuit board 19 Installation member (ceramic circuit board) 20 Closed space 28 Semiconductor integrated circuit chip

Claims (13)

[Claims] An angular velocity measuring device for detecting a rotational angular velocity around a predetermined rotation axis, comprising: a vibrator; a vibrator support member supporting the vibrator; and a circuit board supporting the vibrator support member. And a semiconductor integrated circuit chip for controlling signals of the vibrator, wherein the semiconductor integrated circuit chip is flip-chip mounted on the circuit board, and the vibrator support is mounted on the semiconductor integrated circuit chip. An angular velocity measuring device, wherein a member is installed. 2. The apparatus according to claim 1, wherein said vibrator, said vibrator support member, said circuit board and said semiconductor integrated circuit chip are housed in a can package. 3. The circuit board is a ceramic circuit board, the angular velocity measuring device further includes a lid, and a container is formed by the ceramic circuit board and the lid, and the vibrator is provided in the container. 2. The apparatus according to claim 1, wherein the vibrator support member and the semiconductor integrated circuit chip are accommodated. 4. A stepped portion protruding toward the lid is provided on a mounting surface of the ceramic circuit substrate on which the semiconductor integrated circuit chip is mounted, and a wire from the vibrator is provided to the stepped portion. 4. The device according to claim 3, wherein a bonding is provided. 5. An angular velocity measuring device for detecting a rotational angular velocity around a predetermined rotation axis, comprising: a vibrator; a vibrator support member for supporting the vibrator; and a signal for controlling a signal of the vibrator. A semiconductor integrated circuit chip, a ceramic circuit board for supporting the vibrator support member, and a lid to be combined with the ceramic circuit board. A container is formed by the ceramic circuit board and the lid. An angular velocity measuring device, wherein the vibrator and the vibrator support member are accommodated therein. 6. The semiconductor integrated circuit chip is flip-chip mounted on the ceramic circuit board, and the vibrator support member is supported on the semiconductor integrated circuit chip. The described device. 7. The device according to claim 5, wherein said semiconductor integrated circuit chip is provided on a back surface of said ceramic circuit board opposite to a surface facing said lid. 8. An installation member for installing the semiconductor integrated circuit chip, wherein a closed space is formed by the installation member and the ceramic circuit board, and the semiconductor integrated circuit chip is accommodated in the closed space. The device of claim 5, wherein 9. A stepped portion protruding toward the lid is provided on a mounting surface of the ceramic circuit board on which the semiconductor integrated circuit chip is mounted, and a wire from the vibrator is provided to the stepped portion. Device according to any one of claims 5 to 8, characterized in that a bonding is provided. 10. An angular velocity measuring device for detecting a rotational angular velocity about a predetermined rotation axis, comprising: a vibrator; a vibrator support member supporting the vibrator; and a circuit board supporting the vibrator support member. And a semiconductor integrated circuit chip for controlling a signal of the vibrator, wherein the vibrator is provided on a surface of the circuit board via the vibrator support member, and a back surface of the circuit board is provided. The semiconductor integrated circuit chip is mounted by bare die bonding and wire bonding. An angular velocity estimating device characterized by welding. 11. The apparatus according to claim 1, wherein said vibrator is formed along a predetermined plane, and said predetermined plane is substantially perpendicular to said rotation axis. Apparatus according to claim. 12. The apparatus according to claim 11, wherein said semiconductor integrated circuit chip extends substantially parallel to said vibrator. 13. The apparatus according to claim 1, wherein the temperature of said vibrator is controlled by utilizing heat generated by said semiconductor integrated circuit chip.